Hazardous gases produced by petroleum and coal are major threats to earth's environment. There is a need for alternative green energy sources. Among green energy sources, solar cells and fuel cells are technologies that are growing fast. However, these energy sources are expensive and involve tedious manufacturing processes. The eighteenth century discovery of voltaic piles of zinc and silver disks interweaved with saturated electrolyte absorbent paper brought a revolution in portable power sources. Different combinations of electrodes and electrolytes were experimented. Since then electrochemical batteries are being abundantly used for generating energy by chemical reaction for low power consumption devices. Popular conventional secondary power sources that are used include lithium ion batteries, silver-zinc batteries, lead acid batteries, and alkaline batteries. Among all primary and secondary electrochemical batteries, a combination of electrodes with electrolytes are essential and specific to the power requirement. Modifications in electrode material for electrochemical cells are an ongoing process to improve life and performance of the cell. But electrolytes are still i-s a must for either dry or wet cell chemical reactions to proceed. To improve electrode performance various depolarizer materials have been invented. There are still areas for improvement in existing components and processes of conventional galvanic cells by making modifications in the methods and materials used.
Electrolysis cells with a solid synthetic polymer electrolyte for water dissolution are described in U.S. Pat. Nos. 4,312,436, 4,039,409 and 4,057,479. The limitations for the dissociation of water molecules require bipolar plates with a continuous supply of electricity and water on both sides of the electrolyte membrane attached with a porous catalyst thereof. A tedious manufacturing process is involved in making such an electrolytic cell. Here in this invention a simple and easy hydroelectric cell consisting of a lithium substituted magnesium ferrite pellet with one side having a zinc plate as an anode and other side a silver comb electrode thereof with the ability to dissociate water molecules as well as to cause ion conduction similar to solid electrolyte.
An alkali metal electrode, an alkali ion-conduction membrane and a cathode for separating an alkali metal anode from a cathode are described in U.S. Pat. No. 8,323,817 B2, The limitation of the separation of an electrolyte from contacting and corroding an anode is the critical layer thickness of a porous and non-porous ion-conducting membrane. Another limitation of the described cell is well suited for seawater/marine devices only. Here a solid ceramic material consisting of electrodes of zinc and silver is serving as a water splitter and solid electrolyte for ion conduction. Another important feature of this material is that it can generate energy in pure water without adding any electrolyte.
Another galvanic seawater cell with an inert cathode electrode using oxygen in seawater as a depolarizer is described in U.S. Pat. No. 5,427,871, WO89/11165, PTC/N090/0056. The limitations of these cells is that they required seawater and dissolved oxygen in the cells. The other disadvantage is that seawater contains other metal cations like magnesium, calcium, etc., and gets deposited on a cathode that degraded the performance of the cell. Here in this invention deionized water is used for the cell to generate electric energy. The use of deionised water decreases the probability of premature degradation of the cell due to metal cations on the electrodes, and decreases the performance of the cell.
Humidity sensitivity of Mg1-xLixFe2O4 (0.0<x<0.6) samples prepared by solid-state reaction of inorganic precursors MgSO4, LiNO3, Fe (NO3)3 9H2O, NaOH and NaCl have been described in SCI Journal Sensors And Actuators B 129 (2008) 909-914. The main drawback of the samples is the porosity of the samples is in the range 2.6 to 9.7%. Also NaOH was added to convert metal nitrates and sulfates into hydroxides, whereas NaCl restricted the growth of grains to keep the size as small as possible. Whereas, in the present invention, carbonates of magnesium and lithium and oxides of iron have been used to prepare the sample of porosity 32-38%. No other chemicals other than oxides and carbonates are required.
Ferrites compositions of the formula: LixMg0.5Ni0.5-2xFe2+xO4, where x=0.00 to 0.25 in steps of 0.05, are prepared by a standard double sintering method sintered at a temperature of 1200° C. in air for 6 hours have been described in Advanced Chemistry Letters, 1 (2), 104 (2013). The effect of nickel in magnetic and dielectric properties have been studied in said compound. The limitation of the compound is very high sintering temperature 1200° C. required to synthesize said compound. Porosity of the said compound is between 11-14%. Here, in the present invention, the sintering temperature is lower at 1000° C., and the porosity of the compound is in the range 32-38%.
In the present invention, a simple and easy energy generating cell based on water splitting by lithium substituted magnesium ferrite without adding any electrolyte and a collection of ions using a pair of zinc and silver electrodes has been proposed. The main feature is the ability to generate electrical energy for the time scale of several hours in deionized/ordinary water. In this invention, lithium substituted magnesium ferrite has been synthesized which can dissociate water molecules and allows ion conduction also. To collect the dissociated ions, zinc as an anode electrode and silver as an inert electrode are used on lithium substituted magnesium ferrite pellet. After dipping in deionized water, a 4 mA current and potential of 950 mV is developed across the hydroelectric cell and is stable for 10 minutes. The cell was stable at 0.3 mA and 800 mV even after 380 h. This cell can be reused after ultrasonic cleaning and drying. The output current has been increased to 40 mA and 950 mV for a larger 17 cm2 area cell. The byproducts of the cell reaction are zinc hydroxide and hydrogen gas, which can be further enhanced by a series of a combination of cells. A high purity zinc hydroxide precipitate which is then heated produces zinc oxide nanoparticles obtained by this cell reaction at the anode. As a result of the cell reaction, hydrogen gas is also produced at the inert electrode which can be collected for utilizing as a fuel. No hazardous byproducts are produced by this cell. Another important feature of this hydroelectric cell is the ability to generate economical green electrical energy. So it is a clean energy source with a cost effective price.